Single-chain cd137-receptor agonist proteins

ABSTRACT

Provided herein are specific CD137 receptor agonist proteins, nucleic acids encoding the same, and methods of treating a subject having a CD137L-associated disease or disorder. The CD137 receptor agonist proteins provided herein comprise three soluble CD137L domains and an Fe fragment. The CD137 receptor agonist proteins are substantially non-aggregating and suitable for therapeutic, diagnostic and/or research applications.

This application is a continuation of U.S. patent application Ser. No.15/955,086, filed Apr. 17, 2018; which is a continuation ofPCT/EP2016/075543, filed Oct. 24, 2016; which claims priority to U.S.Provisional Application No. 62/245,838, filed Oct. 23, 2015. Thecontents of the above applications are incorporated herein by referencein their entirety.

REFERENCE TO SEQUENCE LISTING, TABLE OR COMPUTER PROGRAM

The Sequence Listing is concurrently submitted herewith with thespecification as an ASCII formatted text file via EFS-Web with a filename of Sequence_Listing.txt with a creation date of Apr. 11, 2018, anda size of 109 kilobytes. The Sequence Listing filed via EFS-Web is partof the specification and is hereby incorporated in its entirety byreference herein.

FIELD OF THE INVENTION

The present invention provides specific CD137 receptor agonist proteinscomprising three soluble CD137L domains and an Fc fragment, nucleic acidmolecules encoding the CD137 receptor agonist proteins, and usesthereof. The CD137 receptor agonist proteins are substantiallynon-aggregating and suitable for therapeutic, diagnostic and/or researchapplications.

BACKGROUND OF THE INVENTION

It is known that trimerization of TNF superfamily (TNFSF) cytokines isrequired for efficient receptor binding and activation. Trimericcomplexes of TNF superfamily cytokines, however, are difficult toprepare from recombinant monomeric units.

WO 01/49866 and WO 02/09055 disclose recombinant fusion proteinscomprising a TNF cytokine and a multimerization component, particularlya protein from the C1q protein family or a collectin. A disadvantage ofthese fusion proteins is, however, that the trimerization domain usuallyhas a large molecular weight and/or that the trimerization is ratherinefficient.

Schneider et al. (J Exp Med 187 (1989), 1205-1213) describe that trimersof TNF cytokines are stabilized by N-terminally positioned stabilizationmotifs. In CD95L, the stabilization of the receptor binding domaintrimer is presumably caused by N-terminal amino acid domains which arelocated near the cytoplasmic membrane.

Shiraishi et al. (Biochem Biophys Res Commun 322 (2004), 197-202)describe that the receptor binding domain of CD95L may be stabilized byN-terminally positioned artificial α-helical coiled-coil (leucinezipper) motifs. It was found, however, that the orientation of thepolypeptide chains to each other, e.g. parallel or antiparallelorientation, can hardly be predicted. Further, the optimal number ofheptad-repeats in the coiled-coil zipper motif are difficult todetermine. In addition, coiled-coil structures have the tendency to formmacromolecular aggregates after alteration of pH and/or ionic strength.

WO 01/25277 relates to single-chain oligomeric polypeptides which bindto an extracellular ligand binding domain of a cellular receptor,wherein the polypeptide comprises at least three receptor binding sitesof which at least one is capable of binding to a ligand binding domainof the cellular receptor and at least one is incapable of effectivelybinding to a ligand binding domain of the cellular receptor, whereby thesingle-chain oligomeric polypeptides are capable of binding to thereceptor, but incapable of activating the receptor. For example, themonomers are derived from cytokine ligands of the TNF family,particularly from TNF-α.

WO 2005/103077 discloses single-chain fusion polypeptides comprising atleast three monomers of a TNF family ligand member and at least twopeptide linkers that link the monomers of the TNF ligand family membersto one another. Recent experiments, however, have shown that thesesingle chain fusion polypeptides show undesired aggregation.

WO 2010/010051 discloses single-chain fusion polypeptides comprisingthree soluble TNF family cytokine domains and at least two peptidelinkers. The described fusion polypeptides are substantiallynon-aggregating.

Recent studies have shown that the in vivo anti tumor activity of ananti-CD137-mAb is dependent on Fc-gamma-R driven mechanisms and does notrely on agonistic activity only.

There is a need in the art for novel CD137 receptor agonists thatexhibit high biological activity independent of Fc-gamma-R basedcrosslinking in vivo, high stability, and allow for efficientrecombinant manufacturing.

SUMMARY OF THE INVENTION

The present invention provides specific CD137 receptor agonist proteinsthat mimic the CD137:CD137L interaction in vivo, exhibit low proteolyticdegradation and a shorter in vivo half-life as compared to agonisticmonoclonal antibodies.

The CD137 receptor agonist proteins of the instant invention generallycomprise: (i) a first soluble CD137L cytokine domain; (ii) a firstpeptide linker; (iii) a second soluble CD137L domain; (iv) a secondpeptide linker; (v) a third soluble CD137L domain; (vi) a third peptidelinker (e.g., a hinge-linker) and (vii) an antibody Fc fragment.

In one embodiment, the antibody Fc fragment (vii) is located N terminalto the first CD137L domain (i) and/or C-terminal to the third CD137Ldomain (v). In another embodiment the antibody Fc fragment is locatedC-terminally to the third CD137L domain (v). In one embodiment, thepolypeptide is substantially non-aggregating. In another embodiment, thesecond and/or third soluble CD137L domain is an N-terminally shorteneddomain which optionally comprises amino acid sequence mutations. Inanother embodiment, the soluble CD137L domains (i), (ii) and (iii) arean C-terminally shortened domain which optionally comprises amino acidsequence mutations.

In one embodiment, at least one of the soluble CD137L domains,particularly at least one of the soluble CD137L domains (iii) and (v),is a soluble CD137L domain with an N-terminal sequence which starts atamino acid D86 or R88 or Q89 or G90 of human CD137L and wherein D86 orR88 or Q89 may be replaced by a neutral amino acid, e.g., Ser or Gly. Inanother embodiment, at least one of the soluble CD137L domains,particularly at least one of the soluble CD137L domains (iii) and (v),is a soluble CD137L domain with an N-terminal sequences selected from(a) D86-G90 and (b) (Gly/Ser)89-G90. In one embodiment, the solubleCD137L domain ends with amino acid E254 of human CD137L and/oroptionally comprises one or more mutation at positions D86, L87, R88,Q89, D112, V118, A154, A174, A176, A188, T241. In one embodiment, thesoluble CD137L domains (i), (iii) and (v) comprise amino acids D86-E254of human CD137L according to SEQ ID NO: 1.

In one embodiment, at least one of the soluble CD137L domains,particularly at least the soluble CD137L domains (i), is a solubleCD137L domain with an N-terminal sequence which starts at amino acid R88and wherein R88 may be replaced by Ser or Gly. In one embodiment, atleast one of the soluble CD137L domains, particularly at least thesoluble CD137L domain (iii), is a soluble C-terminal shortened CD137Ldomain ending with V240. In another embodiment, at least one of thesoluble CD137L domains, particularly at least the soluble CD137L domains(iii), is a soluble C-terminal shortened CD137L domain ending with T241.In still another embodiment, at least one of the soluble CD137L domains,particularly at least the soluble CD137L domains (iii), is a solubleC-terminal shortened CD137L domain ending with E243.

In one embodiment, the first and second peptide linkers (ii) and (iv)independently have a length of 3-8 amino acids, particularly a length of3, 4, 5, 6, 7, or 8 amino acids, and preferably are glycine/serinelinkers, optionally comprising an asparagine residue which may beglycosylated. In one embodiment, the first and the second peptidelinkers (ii) and (iv) consist of the amino acid sequence according toSEQ ID NO: 2. In another embodiment, the polypeptide additionallycomprises an N-terminal signal peptide domain, e.g., of SEQ ID NO: 17,which may comprise a protease cleavage site, and/or which additionallycomprises a C-terminal element which may comprise and/or connect to arecognition/purification domain, e.g., a Strep-tag attached to a serinelinker according to SEQ ID NO: 18.

In one embodiment, the antibody Fc fragment (vii) is fused to thesoluble CD137L domain (i) and/or (v) via a hinge-linker, preferably ofSEQ ID NO: 16. In another embodiment, the antibody Fc fragment (vii)consists of the amino acid sequence as shown in SEQ ID NO: 13 or 14.

In one embodiment, the single-chain fusion polypeptide of the presentinvention comprises the amino acid sequence selected from the groupconsisting of SEQ ID NO: 15, and 25-35.

In one embodiment, the present invention provides a CD137 receptoragonist protein comprising a dimer of two single-chain fusionpolypeptides each having the amino acid sequence set forth in SEQ ID NO:27. In one embodiment, the two polypeptides are covalently linkedthrough three interchain disulfide bonds formed between cysteineresidues 484, 490, and 493 of each polypeptide. Similar cysteineresidues are positions 484, 490 and 493 of SEQ ID NO: 28, 29 or 32,positions 489, 495 and 498 of SEQ ID NO: 30, positions 493, 499 and 502of SEQ ID NO: 31, and positions 487, 493 and 496 of SEQ ID NO: 33 or 34.

In one embodiment, one or more of the asparagine residues at positions158 and 318 of the mature polypeptide(s) SEQ ID NO: 27, 28 or 29 areN-glycosylated. In another embodiment, the asparagine residues atpositions 158 and 318 of the polypeptide(s) are both N-glycosylated.Similar asparagine residues are positions 161 and 324 of SEQ ID NO: 30or 31, and positions 159 and 320 of SEQ ID NO: 33 or 34.

In another embodiment, the polypeptide(s) are furtherpost-translationally modified. In another embodiment, thepost-translational modification comprises the N-terminal glutamine ofthe D86Q mutein of the first soluble domain (i) modified topyroglutamate.

In still another embodiment, the post-translational modificationcomprises the N-terminal glutamine of the first soluble domain (i)starting with Q89 modified to pyroglutamate.

DESCRIPTION OF THE FIGURES

FIG. 1 Domain structure of a single-chain fusion polypeptide comprisingthree CD137L domains. I., II., III. Soluble CD137L domains.

FIG. 2 Schematic picture representing the general structure of CD137L. ▪▪ ▪ Cell membrane, N-terminus located within the cell,

-   -   1. anti-parallel β-fold of receptor-binding domain (RBD),    -   2. interface of RBD and cell membrane,    -   3. protease cleavage site.

FIG. 3 Single-chain fusion polypeptide comprising an additional Fabantibody fragment.

FIG. 4 Dimerization of two C-terminally fused single-chain Fc fusionpolypeptides via three disulfide bridges.

FIG. 5 Schematic representation of the hexavalent single chain CD27receptor agonist fusion protein of the invention. CH2-Carbohydrates (5)present on the inner surface areas normally shield the CH2-subdomainsterically (2) from proteases during “open Fc-conformation transits”wherein hinge-interchain disulfide bonds (4) are reduced and thecovalent interchain linkage is disrupted. This enables CH2-dissociationand exposure of the inner surface areas and the upper hinge lysine K223(6) towards proteases. Dimer association in the “open stage” remainsintact due to the high affinity of the CH3 domains (3) to each other.

-   -   (1) scCD27L-RBD; (2) CH2 domain; (3) CH3 domain; (4)        Hinge-Cysteines (left side: oxidized to disulfide bridges; right        side reduced stage with free thiols); (5) CH2-Carbohydrates        attached to N297 position (EU-numbering); (6) Upper Hinge Lysine        (K223)

FIG. 6 ELISA assessing the binding of CD137 receptor agonist protein(Protein A) to its receptor

FIG. 7 Analytical size exclusion chromatography of strep tagged ProteinA (SEQ ID NO: 28) performed on a 1260 Infinity HPLC system using a TosohTSKgelG3000SWxl column. The column was loaded with protein at aconcentration of 1 mg/ml in a total volume of 20 μl. The flow rate wasset to 0.5 ml/min. One observes a single main peak at 16.97 min forProtein A. The low molecular weight buffer components of the sampleelute after one column volume (>23.5 min).

FIG. 8 SDS-PAGE results of Protein A under non-reducing and reducingconditions. 360 ng of Protein A were loaded on an SDS-PAGE 4-12%Bis-Tris gel under non-reducing (Lane 1) or reducing (Lane 2) conditionscontaining DTT as reducing agent. Gels were run at 130V for 15 minfollowed by 180V for 60 min and were subsequently stained using asilver-stain protocol. One observes a molecular weight differencebetween the main bands in A and B of about 70-80 kDa. As this is abouthalf the molecular weight as observed for the main band in lane 1, thisindicates that the homodimer in lane 2 is covalently linked by disulfidebridges. The bonds are lost under reducing conditions in lane 2

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a single-chain fusion polypeptidecomprising at least three soluble CD137L domains connected by twopeptide linkers and N-terminally and/or C-terminally an antibody-deriveddimerization domain. The inventors have discovered that dimerization ofthe two single-chain fusion polypeptides through the dimerization domainresults in a hexavalent CD137 receptor agonist, which provides highbiological activity and good stability.

Preferably, the single-chain fusion polypeptide is non-aggregating. Theterm “non-aggregating” refers to a monomer content of the preparation of≥50%, preferably ≥70% and more preferably ≥90%. The ratio of monomercontent to aggregate content may be determined by examining the amountof aggregate formation using size-exclusion chromatography (SEC). Thestability concerning aggregation may be determined by SEC after definedtime periods, e.g. from a few to several days, to weeks and months underdifferent storage conditions, e.g. at 4° C. or 25° C. For the fusionprotein, in order to be classified as substantially non-aggregating, itis preferred that the “monomer” content is as defined above after a timeperiod of several days, e.g. 10 days, more preferably after severalweeks, e.g. 2, 3 or 4 weeks, and most preferably after several months,e.g. 2 or 3 months of storage at 4° C., or 25° C. With regard to thedefinition of “monomer” in the case of FC-fusion proteins, the assemblyof two polypeptide chains is driven by the FC-part and the functionalunit of the resulting assembled protein consists of two chains. Thisunit is defined as “monomer” in the case of Fc-fusion proteinsregardless of being a dimerized single-chain fusion polypeptide.

The single-chain fusion polypeptide may comprise additional domainswhich may be located at the N- and/or C-termini thereof. Examples foradditional fusion domains are e.g. an N-terminal signal peptide domainwhich may comprise a protease cleave site or a C-terminal element whichmay comprise and/or connect to a recognition/purification domain.According to a preferred embodiment, the fusion polypeptide comprises aStrep-tag at its C-terminus that is fused via a linker. An exemplaryStrep-tag including a short serine linker is shown in SEQ ID NO: 18.

The CD137 receptor agonist protein of the present invention comprisesthree soluble domains derived from CD137L. Preferably, those solubledomains are derived from a mammalian, particularly human CD137Lincluding allelic variants and/or derivatives thereof. The solubledomains comprise the extracellular portion of CD137L including thereceptor binding domain without membrane located domains. Like otherproteins of the TNF superfamily, CD137L is anchored to the membrane viaan N-terminal portion of 15-30 amino acids, the so-called stalk-region.The stalk region contributes to trimerization and provides a certaindistance to the cell membrane. However, the stalk region is not part ofthe trimeric receptor binding domain (RBD) with the receptor bindingsites located at the protomer interfaces.

Importantly, the RBD of the Tumor Necrosis Factor Superfamily ischaracterized by a particular localization of its N- and C-terminalamino acids. Said amino acids are immediately adjacent and are locatedin close proximity to the axis of the trimer. The first N-terminal aminoacids of the RBD form an anti-parallel beta-strand with a C-terminalregion of the RBD. Thus, the aforementioned anti-parallel beta-strand ofthe RBD forms an interface with the cell membrane, which is connected toand anchored within the cell membrane via the amino acids of the stalkregion.

Human CD137L contains a stalk region as well as most likely a C-terminalextension (V240-E254).

It is highly preferred that the soluble CD137L domains of the CD137receptor agonist protein comprise a receptor binding domain of theCD137L lacking any amino acids from the stalk region. Otherwise, a longlinker connecting the C-terminus of one of the soluble domains with theN-terminus of the next soluble domain would be required to compensatefor the N-terminal stalk-region of the next soluble domain, which mightresult in instability and/or formation of aggregates. For the samereason, it is also highly preferred that the soluble CD137L domains ofthe CD137 receptor agonist protein comprise a receptor binding domain ofthe CD137L lacking any amino acids from the C-terminal extension.

A further advantage of such soluble domains is that the N-terminal aminoacids of the RBD are not accessible for any anti-drug antibodies.Preferably, the single-chain fusion polypeptide consisting of (i) afirst soluble CD137L domain; (ii) a first peptide linker; (iii) a secondsoluble CD137L domain; (iv) a second peptide linker; (v) a third solubleCD137L domain is capable of forming an ordered structure mimicking thetrimeric organization of its natural counterpart thereby comprising atleast one functional binding site for the respective CD137L receptor.The single-chain fusion polypeptide comprising components (i)-(v) istherefore also termed single-chain-CD137L-receptor-binding-domain(scCD137L-RBD). Importantly, compared to homotrimeric wild typeCD137L-RBD, the scCD137L-RBD comprises an enhanced stability as thesoluble CD137L domains (i), (iii) and (v) are enforced to trimerize bythe covalent linkage to each other provided by the linkers (ii) and(iv).

The CD137 receptor agonist protein comprises three functional CD137receptor binding sites, i.e. amino acid sequences capable of forming acomplex with a CD137 receptor. Thus, the soluble domains are capable ofbinding to the corresponding CD137 receptor. In one embodiment, at leastone of the soluble domains is capable of receptor activation, wherebyapoptotic and/or proliferative activity may be affected. In a furtherembodiment, one or more of the soluble domains are selected as not beingcapable of receptor activation.

The soluble CD137L domain may be derived from human CD137L as shown inSEQ ID NO: 1. Preferably, the soluble CD137L domains are derived fromhuman CD137L, particularly starting from amino acids 86, 88, 89 or 90and comprise particularly amino acids 86-254 or 88-254 or 89-254 of SEQID NO: 1. Optionally, amino acid R88 of SEQ ID NO: 1 may be replaced bya noncharged amino acid, e.g. Ser or Gly or is replaced by Glutamine.

TABLE 1 Sequence of Wild-Type Human CD137L Protein SEQ ID NO Sequence 1MEYASDASLDPEAPWPPAPRARACRVLPWALVAGLLLLLLLAAACAVFLACPWAVSGARASPGSAASPRLREGPELSPDDPAGLLDLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVTPEIPAGLPSPR SE

As indicated above, the soluble CD137L domains may comprise thewild-type sequences as indicated in SEQ ID NO: 1. It should be noted,however, that it is possible to introduce mutations in one or more ofthese soluble domains, e.g. mutations which alter (e.g. increase ordecrease) the binding properties of the soluble domains. In oneembodiment, soluble domains that cannot bind to the correspondingcytokine receptor can be selected.

In a further embodiment of the invention, the soluble CD137L domain (i)comprises a mutant of CD137L or a receptor binding domain thereofresulting in reduced affinity and/or reduced activation of CD137receptor.

CD137L-Muteins Affecting Receptor Binding and/or Activity

The mutant may be generated by any technique known by a skilled person.The substitution may affect at least one amino acid of CD137L, e.g.,human CD137L (e.g., SEQ ID NO: 1) or a receptor binding domain thereofas described herein. Preferred substitutions in this regard affect atleast one of the following amino acids of human CD137L of SEQ ID NO: 1:L115, K127, R150, R193 and Q227.

In another preferred embodiment, the C-terminal region I243-E254 isdeleted from at least one of the soluble domains (i), (III) or (v).

The amino acid substitution(s) may affect the binding and/or activity ofCD137L, e.g., human CD137L, to or on either the CD137 binding or theCD137 induced signaling. The binding and/or activity of the CD137 may beaffected positively, i.e., stronger, more selective or more specificbinding and/or more activation of the receptor. Alternatively, thebinding and/or activity of the CD137 may be affected negatively, i.e.,weaker, less selective or less specific binding and/or less or noactivation of the receptor.

Thus one embodiment is a CD137 receptor agonist protein as describedherein wherein at least one of the soluble domains comprises a mutant ofCD137L or a receptor binding domain thereof which binds and/or activatesCD137 to a lesser extent than the wildtype-CD137L.

CD137L-Muteins with Enhanced Stability/Solubility

In a further embodiment of the invention, one or more of the solubleCD137L domains (i), (iii), and (v) may comprise a mutant of CD137L or areceptor binding domain thereof resulting in reduced self-aggregationand/or prolonged in vivo stability. A174, A176. Preferred substitutionsin this regard are A174[D, N] and A176[S, T]. The mutation(s) of eachCD137L domain may be the same or different.

The single-chain fusion molecule of the present invention comprisesthree soluble CD137L domains, namely components (i), (iii) and (v). Thestability of a single-chain CD137L fusion polypeptide againstaggregation is enhanced, if the second and/or third soluble CD137Ldomain is an N-terminally shortened domain which optionally comprisesamino acid sequence mutations. Thus, preferably, both the second and thethird soluble CD137L domain are N-terminally shortened domains whichoptionally comprise amino acid sequence mutations in the N-terminalregions, preferably within the first five amino acids of the N-terminusof the soluble CD137L domain. These mutations may comprise replacementof basic amino acids, by neutral amino acids, particularly serine orglycine.

In contrast thereto, the selection of the first soluble CD137L domain isnot as critical. Here, a soluble domain having a full-length N-terminalsequence may be used. It should be noted, however, that also the firstsoluble CD137L domain may have an N-terminally shortened and optionallymutated sequence.

In a further preferred embodiment of the present invention, the solubleCD137L domains (i), (iii) and (v) are soluble human CD137L domains. Thefirst soluble CD137L domain (i) may be selected from native, shortenedand/or mutated sequences. Thus, the first soluble CD137L domain (i) hasa N-Terminal sequence which may start at amino acid D86 or R88 of humanCD137L, and wherein R88 may be replaced by a neutral amino acid, e.g. bySer or Gly or by Gln to enable pyroglutamate formation duringexpression. The second and third soluble CD137L domains (iii) and (v)have a shortened N-terminal sequence which preferably starts with aminoacid Q89 or G90 of human CD137L (SEQ ID NO:1) and wherein Q89 may bereplaced by another amino acid, e.g. Ser or Gly.

Preferably, the N-terminal sequence of the soluble CD137L domains (iii)and (v) is selected from:

(a) D86 or Q89

(b) (Gly/Ser) 89

The soluble CD137L domain preferably ends with amino acid E254 of humanCD137L. In certain embodiments, the CD137L domain may comprise internalmutations as described above.

In another preferred embodiment, the soluble CD137L domain preferablyends with amino acid V240 of human CD137L. In certain embodiments, theCD137L domain may comprise internal mutations as described above.

Components (ii) and (iv) of the CD137 receptor agonist protein arepeptide linker elements located between components (i) and (iii) or(iii) and (v), respectively. The flexible linker elements have a lengthof 3-8 amino acids, particularly a length of 3, 4, 5, 6, 7, or 8 aminoacids. The linker elements are preferably glycine/serine linkers, i.e.peptide linkers substantially consisting of the amino acids glycine andserine. In cases in in which the soluble cytokine domain starts with Sor G (N-terminus), the linker ends before this S or G.

It should be noted that linker (ii) and linker (iv) do not need to be ofthe same length. In order to decrease potential immunogenicity, it maybe preferred to use shorter linkers. In addition it turned out thatshorter linkers lead to single chain molecules with reduced tendency toform aggregates. Whereas linkers that are substantially longer than theones disclosed here may exhibit unfavorable aggregations properties.

If desired, the linker may comprise an asparagine residue which may forma glycosylate site Asn-Xaa-Ser. In certain embodiments, one of thelinkers, e.g. linker (ii) or linker (iv) comprises a glycosylation site.In other embodiments, both linkers (iv) comprise glycosylation sites. Inorder to increase the solubility of the CD137L agonist proteins and/orin order to reduce the potential immunogenicity, it may be preferredthat linker (ii) or linker (iv) or both comprise a glycosylation site.

Preferred linker sequences are shown in Table 2. A preferred linker isGSGSGNGS (SEQ ID NO: 2).

TABLE 2 Example Linker Sequences SEQ ID NO Sequence 2 GSGSGNGS 3GSGSGSGS 4 GGSGSGSG 5 GGSGSG 6 GGSG 7 GGSGNGSG 8 GGNGSGSG 9 GGNGSG 10GSGSGS 11 GSGS 12 GSG

The CD137 receptor agonist protein additionally comprises an antibody Fcfragment domain which may be located N-terminal to the first CD137Ldomain (i) and/or C-terminal to the third CD137L domain (v). Preferably,the antibody Fc fragment domain comprises a reduced capability tointeract with Fc-gamma-R receptors in vivo. Preferably, the antibody Fcfragment domain comprises or consists of an amino acid sequence as shownin SEQ ID NO: 13 or 14 (see Table 3). Sequence ID NO: 13 has N297Smutation compared to wildtype human IGG1-Fc. Sequence ID NO: 14 is aglycosylated (N297 wildtype) human IGG1 Fc mutein with reducedFc-gamma-R binding capability.

TABLE 3 Examples of Fc Fragment Domains SEQ ID NO Sequence 13PAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQK SLSLSPGK 14PAPPVAGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKS LSLSPGK

Number of Glycosylation Sites and In Vivo Stability

The total number of glycosylation sites and the individual position ofthe carbohydrates in three dimensions impacts the in-vivo stability ofCD137 receptor agonist proteins. Further, carbohydrate recognitiondepends on local density of the terminal saccharides, the branching ofthe carbohydrate tree and the relative position of the carbohydrates toeach other matter.

Further, partially degraded carbohydrates reduce the in vivo half-lifeof CD137 receptor agonist proteins through lectin-driven mechanisms. Byreducing the total number of glycosylation sites on the molecule, theresulting compound is less accessible to these mechanisms, increasinghalf-life.

Depletion of the CH2-domain carbohydrates of the Fc-domain is necessaryin order to avoid Fc-gamma-Receptor based binding. FcR-gamma-Receptorson cells could lead to hyper-crosslinking of the fusion-protein in vivopotential leading to CD137-receptor superclustering-based toxicity.Also, unwanted Fc-driven mechanisms like ADCC could lead to toxicevents. Accordingly, in one embodiment, the overall number ofglycosylation sites on the CD137 receptor agonist proteins of theinstant invention is reduced through the depletion of CH2 glycosylationsites, particularly the N-glycosylation site, resulting in CD137receptor agonist proteins comprising N297S equivalent mutations of SEQID NO: 15 (PROTEIN A) (according to the EU numbering system) creatingaglycosl-CH2 domains.

CH2-Domain Destabilization is Compensated by an AdditionalHinge-Cysteine

CH2-glycosylation present on the inner surface areas normally shieldsthe subdomain from proteases during “open Fc-conformation transits”wherein hinge-interchain disulfide bonds are reduced and the covalentinterchain linkage is disrupted. This enables CH2-dissociation andexposure of the inner surface area towards proteases. CD137 receptoragonist proteins comprising an Fc-domain with a N297S equivalentmutation of SEQ ID NO: 15 (PROTEIN A) (according to the EU numberingsystem) creates an a glycosylated-CH2 and are therefore likely to besubject to protease digestion and less stable than equivalent structureswith wild-type CH2 glycosylation. This would impact the compound'sstability during USP/DSP/storage, where host cell proteases are presentand have long-term access to the structure. Accordingly, in certainembodiments, the CD137 receptor agonist lacks CH2 glycosylation sites,but comprises glycosylation sites in the linker sequences of eachpolypeptide chain (e.g., GSGSGNGS, SEQ ID NO: 2).

According to a preferred embodiment of the invention, the antibody Fcfragment domain is fused via a hinge linker element. The hinge-linkerelement has a length of 10-30 amino acids, particularly a length of15-25 amino acids, e.g. 22 amino acids. The term “hinge-linker” includesany linker long enough to allow the domains attached by the hinge linkerelement to attain a biologically active confirmation. The hinge-linkerelement preferably comprises the hinge-region sequence of animmunoglobulin, herein referred to as “Ig hinge-region”. The term “Ighinge region” means any polypeptide comprising an amino acid sequencethat shares sequence identity or similarity with a portion of anaturally occurring Ig hinge-region sequence which includes one or morecysteine residues, e.g., two cysteine residues, at which the disulfidebonds link the two heavy chains of the immunoglobulin.

Derivatives and analogues of the hinge-region can be obtained bymutations. A derivative or analogue as referred to herein is apolypeptide comprising an amino acid sequence that shares sequenceidentity or similarity with the full length sequence of the wild type(or naturally occurring protein) except that it has one or more aminoacid sequence differences attributable to a deletion, insertion and/orsubstitution.

The number of molecules with open Fc-conformation in an individual CD137receptor agonist protein depends on the number of interchain-disulfidebonds present in the hinge region. Accordingly, in one embodiment athird cysteine (C225 according to the EU numbering system) wasintroduced into the hinge region of the CD137 receptor agonist proteinsof the instant invention in order to ameliorate the effect of depletingthe CH2-glycosites.

Exchange of a Lysine to Glycine in the Hinge Region Results in EnhancedProteolytic Stability

In one embodiment, the CD137 receptor agonist proteins of the inventionadditionally comprise a mutation of the upper-hinge lysine (K223,according to the EU numbering system) to a glycine to reduce proteolyticprocessing at this site, thereby enhancing the overall stability of thefusion protein. Combining aforementioned introduction of a thirdcysteine (C225, according to the EU numbering system) with theaforementioned lysine to glycine mutation (K223G, according to the EUnumbering system) within the hinge region results in an overallstabilized CD137 receptor agonist protein of the instant invention.

A particularly preferred hinge-linker element including theaforementioned cysteine (C225) and the lysine to glycine mutation(K223G) comprises or consists of the amino acid sequence as shown in SEQID NO: 16 (Table 4).

The CD137 receptor agonist protein may additionally comprise anN-terminal signal peptide domain, which allows processing, e.g.extracellular secretion, in a suitable host cell. Preferably, theN-terminal signal peptide domain comprises a protease cleavage site,e.g. a signal peptidase cleavage site and thus may be removed after orduring expression to obtain the mature protein. A particularly preferredN-terminal signal peptide domain comprises the amino acid sequence asshown in SEQ ID NO: 17 (Table 4).

Further, the CD137 receptor agonist protein may additionally comprise aC-terminal element, having a length of e.g. 1-50, preferably 10-30 aminoacids which may include or connect to a recognition/purification domain,e.g. a FLAG domain, a Streptag or Strep-tag II domain and/or a poly-Hisdomain. According to a preferred embodiment, the fusion polypeptidecomprises a Streptag fused to the C-terminus via a short serine linkeras shown in SEQ ID NO: 18 (Table 4).

Preferred hinge-linker elements (SEQ ID NO: 16, 19-24), a preferredN-terminal signal peptide domain (SEQ ID NO: 17) and a preferred serinelinker-strep tag (SEQ ID NO: 18) are shown in Table 4.

TABLE 4 Exemplary domains and linkers SEQ ID NO Sequence 16GSSSSSSSSGSCDKTHTCPPC 17 METDTLLVFVLLVWVPAGNG 18 SSSSSSAWSHPQFEK 19GSSSSSSSGSCDKTHTCPPC 20 GSSSSSSGSCDKTHTCPPC 21 GSSSSSGSCDKTHTCPPC 22GSSSGSCDKTHTCPPC 23 GSSSGSCDKTHTCPPCGS 24 GSSSGSCDKTHTCPPCGSGS

In one embodiment of the invention, the fusion polypeptide comprisesthree soluble CD137L domains fused by peptide linker elements of SEQ IDNO: 2. All three soluble CD137L domain (i), (iii), (v) consists of aminoacids 89-240 of human CD137L according to SEQ ID NO: 1. The resultingscCD137L-RBD sequence module is shown in table 5b SEQ ID NO: 36.

In a further preferred embodiment of the invention, the fusionpolypeptide comprises three soluble CD137L domains fused by peptidelinker elements of SEQ ID NO: 2. All three soluble CD137L domain (i),(iii), (v) consists of amino acids 86-240 of human CD137L according toSEQ ID NO: 1 with D86Q mutation in the first domain (i). The resultingscCD137L-RBD sequence module is shown in table 5b SEQ ID NO: 39.

In another embodiment of the invention, the fusion polypeptide comprisesthree soluble CD137L domains fused by peptide linker elements of SEQ IDNO: 2. All three soluble CD137L domain (i), (iii), (v) consists of aminoacids 88-240 of human CD137L according to SEQ ID NO: 1. The resultingscCD137L-RBD sequence module is shown in table 5b SEQ ID NO: 40.

In still another preferred embodiment of the invention, the fusionpolypeptide comprises three soluble CD137L domains fused by peptidelinker elements of SEQ ID NO: 2. All three soluble CD137L domain (i),(iii), (v) consists of amino acids 88-240 of human CD137L according toSEQ ID NO: 1 with R88Q mutation in the first domain (i) and R88Gmutation in domains (iii) and (v). The resulting scCD137L-RBD sequencemodule is shown in table 5b SEQ ID NO: 41.

In still another preferred embodiment of the invention, the fusionpolypeptide comprises three soluble CD137L domains fused by peptidelinker elements of SEQ ID NO: 2. All three soluble CD137L domain (i),(iii), (v) consists of amino acids 88-240 of human CD137L according toSEQ ID NO: 1 with R88S mutation in the first domain (i) and R88Gmutation in domains (iii) and (v). The resulting scCD137L-RBD sequencemodule is shown in table 5b SEQ ID NO: 42.

In still another preferred embodiment of the invention, the fusionpolypeptide comprises three soluble CD137L domains fused by peptidelinker elements of SEQ ID NO: 2. All three soluble CD137L domain (i),(iii), (v) consists of amino acids 89-240 of human CD137L according toSEQ ID NO: 1 and comprise the A174N and A176S mutations. The resultingscCD137L-RBD sequence module is shown in table 5b SEQ ID NO: 43.

The aforementioned scCD137L-RBD modules (SEQ ID: 36, 39-43) are wellsuited to generate fusion proteins with additional domains fused toeither N- or C-terminal end employing the linkers described in Table 2(SEQ ID NO: 2-12).

Preferred Configuration CD137L-Fc

Additionally, the fusion polypeptide comprises an antibody Fc fragmentdomain according to SEQ ID NO: 13 that is fused C-terminally to thesoluble CD137L domain (v) via a hingelinker according to SEQ ID NO: 16.The inventors surprisingly found that this particular fusion polypeptideprovides improved biological activity as compared to bivalent agonisticanti-CD137-mAB and has a prolonged stability as compared to fusionproteins comprising a lysine in position 223 and a N297S mutation in theCH2 domain (according to the EU numbering).

The amino acid sequence of an exemplary embodiment of a CD137 receptoragonist protein of the invention is set forth in SEQ ID NO: 27.

Further, the fusion polypeptide may comprise an N-terminal signalpeptide domain e.g. according to SEQ ID NO: 17. A specific example of aCD137 receptor agonist protein of the invention is shown in SEQ ID NO:25.

According to another preferred embodiment, the fusion polypeptide mayadditionally comprise a C-terminal Strep-tag that is fused to thepolypeptide of the invention via a short serine linker as shown in SEQID NO: 18. According to this aspect of the invention, the Fc fragmentpreferably consists of the amino acid sequence as shown in SEQ ID NO: 13or 14. Further, the Fc fragment may consist of a shorter Fc fragment,for example including amino acids 1217 of SEQ ID NO: 13. Particularlypreferred examples of fusion polypeptides comprising a C-terminalStrep-tag are shown in SEQ ID NO: 15 (PROTEIN A).

The exemplary CD137 receptor agonist proteins as shown in SEQ ID Nos:15, 25, and 26, each comprises an N-terminal signal peptide domain, atamino acids 1-20 of each sequence. In each case, the mature proteinstarts with amino acid 21. Mature exemplary CD137 receptor agonistproteins (without a signal peptide) of the instant invention are setforth in SEQ ID NO: 27-35. Exemplary CD137 receptor agonist proteinsdescribed above are shown in Table 5.

The CD137 receptor agonist as set forth in SEQ ID NO: 27 has a reducedtotal number of glycosylation sites (the N297S mutation in the CH2region providing an a glycosylated CH2 domain, according to the EUnumbering system), an increased number of interchain disulfide bonds inthe hinge region, and the mutation of an upper-hinge lysine to a glycine(K223G, according to the EU numbering system). These alterations providea decrease in potential degradation and CD137 receptor superclustering(along with concomitant toxicity).

The CD137 receptor agonist as set forth in SEQ ID NO: 30 comprises ascCD137L-RBD module with SEQ ID NO: 36, a third peptide linker with SEQID NO: 21 and (vii) an antibody Fc fragment with SEQ ID NO: 13.

The CD137 receptor agonist as set forth in SEQ ID NO: 31 comprises ascCD137L-RBD module with SEQ ID NO: 39, a third peptide linker with SEQID NO: 16 and (vii) an antibody Fc fragment with SEQ ID NO: 13.

The CD137 receptor agonist as set forth in SEQ ID NO: 32 comprises ascCD137L-RBD module with SEQ ID NO: 40, a third peptide linker with SEQID NO: 16 and (vii) an antibody Fc fragment with SEQ ID NO: 13.

The CD137 receptor agonist as set forth in SEQ ID NO: 33 comprises ascCD137L-RBD module with SEQ ID NO: 41, a third peptide linker with SEQID NO: 16 and (vii) an antibody Fc fragment with SEQ ID NO: 13.

The CD137 receptor agonist as set forth in SEQ ID NO: 34 comprises ascCD137L-RBD module with SEQ ID NO: 42, a third peptide linker with SEQID NO: 16 and (vii) an antibody Fc fragment with SEQ ID NO: 13.

TABLE 5 Exemplary CD137 receptor agonist proteins SEQ ID NO Sequence 25METDTLLVFVLLVWVPAGNGQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLS PROTEIN AYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALT withoutVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFR StrepTagVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVICVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLICLVKGFYPSDIAVEWESNGQPENNYKTIPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 15METDTLLVFVLLVWVPAGNGQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLS PROTEIN AYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVICVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLICLVKGFYPSDIAVEWESNGQPENNYKTIPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGSSSSSSAWSHP QFEK 26METDTLLVFVLLVWVPAGNGQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLS CD137L-wt +YKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALT SEQ14VDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGS5555SSSGSCDKTHTCPPCPAPPVAGPSVFLFPPKPKDTLMISRIPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 27QGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFF CD137L-wt +QLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGR SEQ13 FCLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQN No SignalVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGE No StrepGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLG No GlycoVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 28QGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFF Deg lyco-FcQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGR No Signal +LLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQN StrepTagVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGSSSSSSAWSHPQFEK 29QGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFF Glyco FCQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGR No SignalLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQN No strepVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGS5555SSSGSCDKTHTCPPCPAPPVAGPSVFLFPPKPKDTLMISRIPEVICVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKGLPSSIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 30QLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYY SEQ39 + FCVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGF 13QGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSDLRQGMFA Linker 21QLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSDLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDILMISRIPEVICVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 31QLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSDLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSDLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRIPEVICVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 32RQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDILMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 33QQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDILMISRIPEVICVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 34SQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVICVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK 35QGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFF (Seq27 withQLELRRVVAGEGSGSVSLALHLQPLRSANGSAALALTVDLPPASSEARNSAFGFQGR additionalLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQN glycol-sites)VLLIDGPLSWYSDPGLAGVSLIGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSANGSAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSANGSAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSSSSSSSSGSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYSSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK

TABLE 5B Exemplary scCD137L-RBD modules 36QGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRV 39QLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSDLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSDLRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFR V 40RQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSRQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRV 41QQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRV 42SQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSgQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRV 43QGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSANGSAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSANGSAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSGNGSQGMFAQLVAQNVLLIDGPLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVFFQLELRRVVAGEGSGSVSLALHLQPLRSANGSAALALTVDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRV

A further aspect of the present invention relates to a nucleic acidmolecule encoding a CD137 receptor agonist protein as described herein.The nucleic acid molecule may be a DNA molecule, e.g. a double-strandedor single-stranded DNA molecule, or an RNA molecule. The nucleic acidmolecule may encode the CD137 receptor agonist protein or a precursorthereof, e.g. a pro- or pre-proform of the CD137 receptor agonistprotein which may comprise a signal sequence or other heterologous aminoacid portions for secretion or purification which are preferably locatedat the N- and/or C-terminus of the CD137 receptor agonist protein. Theheterologous amino acid portions may be linked to the first and/orsecond domain via a protease cleavage site, e.g. a Factor X3, thrombinor IgA protease cleavage site. A specific example of a nucleic acidsequence of the invention is shown in Table 6 as SEQ ID NO: 37. Thisnucleic acid molecule comprises the open reading frame encoding thefusion polypeptide of SEQ ID NO: 25.

TABLE 6 Nucleic Acid Sequence of ExemplaryC0137 receptor agonist protein SEQ ID NO Sequence 37AAGCTTTAGGGATAACAGGGTAATAGCCGCCACCATGGAGACTGACACCCTGCTGGTGTTCGTGCTGCTGGTCTGGGTGCCTGCAGGAAATGGACAGGGCATGTTCGCTCAACTGGTCGCACAGAACGTGCTGCTCATTGACGGTCCCCTGTCTTGGTACTCCGATCCAGGGTTGGCAGGAGTGTCCTTGACAGGAGGGCTGTCCTATAAGGAGGATACCAAAGAGCTGGTGGTAGCAAAGGCTGGTGTGTATTACGTGTTCTTTCAGCTGGAGCTGCGCAGAGTCGTCGCAGGCGAAGGATCTGGTAGTGTGTCACTGGCACTGCACTTGCAGCCCCTTCGGTCCGCTGCCGGGGCAGCAGCACTGGCCCTGACCGTCGATCTGCCACCCGCTTCTAGCGAGGCACGAAACTCAGCCTTTGGGTTTCAGGGTCGCCTGCTGCACCTGAGCGCCGGACAGAGGCTGGGCGTTCATCTGCACACCGAGGCCAGAGCCAGACACGCTTGGCAGTTGACTCAGGGAGCTACGGTCCTCGGTCTGTTTCGAGTAGGCAGCGGAAGCGGCAATGGCTCTCAGGGCATGTTTGCTCAGCTGGTAGCCCAGAACGTACTCCTGATCGATGGCCCTCTTTCATGGTACTCAGACCCCGGACTGGCCGGAGTTAGCCTTACAGGTGGGCTTAGTTATAAGGAGGACACAAAGGAATTGGTTGTGGCCAAAGCTGGCGTGTACTATGTGTTCTTCCAGCTTGAGCTCCGCAGAGTCGTGGCTGGGGAGGGCTCTGGCAGTGTGAGCCTTGCCCTTCATCTGCAACCTTTGCGGAGCGCAGCCGGCGCTGCTGCACTGGCCCTTACAGTGGATTTGCCACCCGCAAGTAGTGAAGCTCGCAATTCCGCATTCGGTTTCCAGGGCCGTCTGCTCCATCTTTCTGCCGGTCAACGTCTGGGAGTTCACCTCCACACTGAGGCTAGGGCCAGGCATGCTTGGCAGCTGACTCAAGGAGCCACTGTCTTGGGACTCTTTCGGGTAGGCTCCGGGTCTGGCAACGGCTCCCAGGGGATGTTTGCCCAACTGGTCGCCCAGAATGTCCTGCTCATCGATGGTCCTCTGAGCTGGTATTCCGACCCTGGACTGGCTGGTGTGAGCCTGACTGGCGGACTCTCCTACAAAGAGGACACCAAGGAACTGGTGGTGGCCAAAGCCGGGGTGTACTACGTGTTCTTCCAGTTGGAACTGCGGCGGGTTGTGGCTGGCGAGGGATCAGGTTCCGTTAGTCTGGCCCTGCACCTCCAGCCTCTGAGGTCTGCTGCTGGTGCCGCCGCTCTGGCCTTGACCGTCGACCTCCCACCCGCATCTTCCGAAGCCCGAAATTCAGCCTTCGGGTTCCAGGGCAGACTGCTGCATCTGAGTGCTGGACAGCGCCTTGGGGTTCATCTCCACACCGAAGCCAGGGCCCGACATGCCTGGCAGCTCACACAAGGCGCAACCGTTTTGGGGCTCTTTCGTGTGggatcctcgagTTCATCGTCCTCATCCGGCTCATGTGATAAGACCCACACCTGCCCTCCCTGTCCTGCCCCTGAGCTGCTGGGCGGACCTTCTGTGTTCCTGTTCCCCCCCAAGCCTAAGGACACCCTGATGATCTCCAGGACCCCTGAGGTGACCTGTGTGGTGGTGGACGTGTCTCACGAAGATCCCGAGGTGAAGTTCAACTGGTACGTGGACGGCGTGGAGGTCCACAACGCCAAGACCAAGCCTAGGGAGGAGCAGTACAGCTCCACCTACCGGGTGGTGTCTGTGCTGACCGTGCTGCACCAGGATTGGCTGAACGGAAAGGAGTATAAGTGTAAGGTCTCCAACAAGGCCCTGCCTGCCCCCATCGAGAAAACCATCTCCAAGGCCAAGGGCCAGCCTCGGGAGCCTCAGGTGTACACCCTGCCTCCTAGCAGGGAGGAGATGACCAAGAACCAGGTGTCCCTGACCTGTCTGGTGAAGGGCTTCTACCCTTCCGATATCGCCGTGGAGTGGGAGTCTAATGGCCAGCCCGAGAACAACTACAAGACCACCCCTCCTGTGCTGGACTCTGACGGCTCCTTCTTCCTGTACTCCAAGCTGACCGTGGACAAGTCCAGATGGCAGCAGGGCAACGTGTTCTCCTGCTCCGTGATGCACGAGGCCCTGCACAATCACTACACCCAGAAGTCCCTGTCTCTGAGTCCGGGCAA GTAATAggcgcgcc 

The nucleic acid molecule may be operatively linked to an expressioncontrol sequence, e.g. an expression control sequence which allowsexpression of the nucleic acid molecule in a desired host cell. Thenucleic acid molecule may be located on a vector, e.g. a plasmid, abacteriophage, a viral vector, a chromosomal integration vector, etc.Examples of suitable expression control sequences and vectors aredescribed for example by Sambrook et al. (1989) Molecular Cloning, ALaboratory Manual, Cold Spring Harbor Press, and Ausubel et al. (1989),Current Protocols in Molecular Biology, John Wiley & Sons or more recenteditions thereof.

Various expression vector/host cell systems may be used to express thenucleic acid sequences encoding the CD137 receptor agonist proteins ofthe present invention. Suitable host cells include, but are not limitedto, prokaryotic cells such as bacteria, e.g. E. coli, eukaryotic hostcells such as yeast cells, insect cells, plant cells or animal cells,preferably mammalian cells and, more preferably, human cells. Further,the invention relates to a non-human organism transformed or transfectedwith a nucleic acid molecule as described above. Such transgenicorganisms may be generated by known methods of genetic transferincluding homologous recombination.

A further aspect of the present invention relates to a pharmaceutical ordiagnostic composition comprising as the active agent at least one CD137receptor agonist protein, a respective nucleic acid encoding therefore,or a transformed or transfected cell, all as described herein.

In another aspect, the present invention provides a pharmaceuticalcomposition comprising an CD137 receptor agonist protein disclosedherein and one or more pharmaceutically acceptable carriers, diluents,excipients, and/or adjuvants. In another aspect, the present inventionprovides a nucleic acid molecule encoding the CD137 receptor agonistprotein. In another embodiment, the present invention provides anexpression vector comprising the nucleic acid molecule. In anotherembodiment, the present invention provides a cell comprising the nucleicacid molecule. In a further embodiment, the cell is a eukaryotic cell.In another embodiment, the cell is a mammalian cell. In anotherembodiment, the cell is a Chinese Hamster Ovary (CHO) cell. In otherembodiments, the cell is selected from the group consisting ofCHO-DBX11, CHO-DG44, CHO-S, and CHO-K1 cells. In other embodiments, thecell is selected from the group consisting of Vero, BHK, HeLa, COS,MDCK, HEK-293, NIH-3T3, W138, BT483, Hs578T, HTB2, BT20, T47D, NS0,CRL7030, HsS78Bst, PER.C6, SP2/0-Agl4, and hybridoma cells.

In another aspect, the present invention provides a method of treating asubject having an CD137L-associated disease or disorder, the methodcomprising administering to the subject an effective amount of the CD137receptor agonist protein. In one embodiment, the CD137 receptor agonistprotein is administered alone. In another embodiment, the CD137 receptoragonist protein is administered before, concurrently, or after theadministration of a second agent. In another embodiment, the disease ordisorder is selected from the group consisting of: tumors, infectiousdiseases, inflammatory diseases, metabolic diseases, autoimmunedisorders, degenerative diseases, apoptosis-associated diseases, andtransplant rejections. In one embodiment, the tumors are solid tumors.In one embodiment, the tumors arise from the group of cancers consistingof sarcoma, esophageal cancer, and gastric cancer. In anotherembodiment, the tumors arise from Ewing's sarcoma or fibrosarcoma. Inanother embodiment, the tumors arise from the group of cancersconsisting of Non-Small Cell Lung Carcinoma (NSCLC), pancreatic cancer,colorectal cancer, breast cancer, ovarian cancer, head and neck cancers,and Small Cell Lung Cancer (SCLC). In another embodiment, the tumors arelymphatic tumors. In one embodiment, the tumors are hematologic tumors.In another embodiment, the tumors arise from non-Hodgkin's lymphoma,leukemia, acute lymphoblastic leukemia (ALL), acute myeloid leukemia(AML), B cell lymphoma, Burkitt's lymphoma, chronic myelocytic leukemia(CML), chronic lymphocytic leukemia (CLL), or hairy cell leukemia. Inanother embodiment, the autoimmune disorders are rheumatoid diseases,arthritic diseases, or rheumatoid and arthritic diseases. In a furtherembodiment, the disease or disorder is rheumatoid arthritis. In anotherembodiment, the degenerative disease is a neurodegenerative disease. Ina further embodiment, the neurodegenerative disease is multiplesclerosis.

In one embodiment, the second agent is a chemotherapeutic,radiotherapeutic, or biological agent. In one embodiment, the secondagent is selected from the group consisting of Duvelisib, Ibrutinib,Navitoclax, and Venetoclax. In another embodiment, the second agent isan apoptotic agent. In one embodiment, the apoptotic second agent isselected from the group consisting of Bortezomib, Azacitidine,Dasatinib, and Gefitinib. In a particular embodiment, the pharmaceuticalcompositions disclosed herein are administered to a patient byintravenous or subcutaneous administration. In other embodiments, thedisclosed pharmaceutical compositions are administered to a patientbyoral, parenteral, intramuscular, intrarticular, intrabronchial,intraabdominal, intracapsular, intracartilaginous, intracavitary,intracelial, intracerebellar, intracerebroventricular, intracolic,intracervical, intragastric, intrahepatic, intramyocardial, intraosteal,intrapelvic, intrapericardiac, intraperitoneal, intrapleural,intraprostatic, intrapulmonary, intrarectal, intrarenal, intraretinal,intraspinal, intrasynovial, intrathoracic, intrauterine, intravesical,bolus, vaginal, rectal, buccal, sublingual, intranasal, or transdermaladministration.

In one embodiment, the CD137 receptor agonist protein is administered asa single bolus. In another embodiment, CD137 receptor agonist proteinmay be administered over several divided doses. The CD137 receptoragonist protein can be administered at about 0.1-100 mg/kg. In oneembodiment, the CD137 receptor agonist protein can be administered at adosage selected from the group consisting of: about 0.1-0.5, 0.1-1,0.1-10, 0.1-20, 0.1-50, 0.1-75, 1-10, 1-15, 1-7.5, 1.25-15, 1.25-7.5,2.5-7.5, 2.5-15, 5-15, 5-7.5, 1-20, 1-50, 7-75, 1-100, 5-10, 5-15, 5-20,5-25, 5-50, 5-75, 10-20, 10-50, 10-75, and 10-100 mg/kg. In otherembodiments, the CD137 receptor agonist protein is present inpharmaceutical compositions at about 0.1-100 mg/ml. In one embodiment,the CD137 receptor agonist protein is present in pharmaceuticalcompositions at an amount selected from the group consisting of: about0.1-0.5, 0.1-1, 0.1-10, 0.1-20, 0.1-50, 0.1-75, 1-10, 1-20, 1-50, 1-75,1-100, 5-10, 5-15, 5-20, 5-25, 5-50, 5-75, 10-20, 10-50, 10-75, or10-100 mg/ml. In other embodiments, a therapeutically effective amountof CD137 receptor agonist protein is administered to a subject. Inanother embodiment, a prophylactically effective amount of CD137receptor agonist protein is administered to a subject.

The term “CD137L-associated disease or disorder” as used herein is anydisease or disorder which may be ameliorated by administering aneffective amount of a CD137 receptor agonist to a subject in needthereof. At least one CD137 receptor agonist protein, respective nucleicacid encoding therefore, or transformed or transfected cell, all asdescribed herein may be used in therapy, e.g., in the prophylaxis and/ortreatment of disorders caused by, associated with and/or accompanied bydysfunction of CD137L, particularly proliferative disorders, such astumors, e.g. solid or lymphatic tumors; infectious diseases;inflammatory diseases; metabolic diseases; autoimmune disorders, e.g.rheumatoid and/or arthritic diseases; degenerative diseases, e.g.neurodegenerative diseases such as multiple sclerosis;apoptosis-associated diseases or transplant rejections.

-   -   The term “dysfunction of CD137L” as used herein is to be        understood as any function or expression of CD137L that deviates        from the normal function or expression of CD137L, e.g.,        overexpression of the CD137L gene or protein, reduced or        abolished expression of the CD137L gene or protein compared to        the normal physiological expression level of CD137L, increased        activity of CD137L, reduced or abolished activity of CD137L,        increased binding of CD137L to any binding partners, e.g., to a        receptor, particularly a CD137L receptor or another cytokine        molecule, reduced or abolished binding to any binding partner,        e.g. to a receptor, particularly a CD137L receptor or another        cytokine molecule, compared to the normal physiological activity        or binding of CD137L.

In various embodiments, a method is provided for diagnosing and/ortreating a human subject suffering from a disorder which can bediagnosed and/or treated by targeting CD137L receptors comprisingadministering to the human subject a CD137 receptor agonist proteindisclosed herein such that the effect on the activity of the target, ortargets, in the human subject is agonistic, one or more symptoms isalleviated, and/or treatment is achieved. The CD137 receptor agonistproteins provided herein can be used to diagnose and/or treat humanssuffering from primary and metastatic cancers, including carcinomas ofbreast, colon, rectum, lung (e.g., small cell lung cancer “SCLC” andnon-small cell lung cancer “NSCLC”), oropharynx, hypopharynx, esophagus,stomach, pancreas, liver, gallbladder and bile ducts, small intestine,urinary tract (including kidney, bladder and urothelium), female genitaltract (including cervix, uterus, and ovaries as well as choriocarcinomaand gestational trophoblastic disease), male genital tract (includingprostate, seminal vesicles, testes and germ cell tumors), endocrineglands (including the thyroid, adrenal, and pituitary glands), and skin,as well as hemangiomas, melanomas, sarcomas (including those arisingfrom bone and soft tissues as well as Kaposi's sarcoma), tumors of thebrain, nerves, eyes, and meninges (including astrocytomas, gliomas,glioblastomas, retinoblastomas, neuromas, neuroblastomas, Schwannomas,and meningiomas), tumors arising from hematopoietic malignancies, acuteleukemia, acute lymphoblastic leukemia (ALL), acute myeloid leukemia(AML), B cell lymphoma, Burkitt's lymphoma, chronic myelocytic leukemia(CML), chronic lymphocytic leukemia (CLL), hairy cell leukemia,Hodgkin's and non-Hodgkin's lymphomas, DLBCL, follicular lymphomas,hematopoietic malignancies, Kaposi's sarcoma, malignant lymphoma,malignant histiocytosis, malignant melanoma, multiple myeloma,paraneoplastic syndrome/hypercalcemia of malignancy, or solid tumors.

A pharmaceutical composition comprising a CD137 receptor agonist proteindisclosed herein and a pharmaceutically acceptable carrier is provided.In some embodiments, the pharmaceutical composition comprises at leastone additional therapeutic agent for treating a disorder. For example,the additional agent may be a therapeutic agent, a chemotherapeuticagent; an imaging agent, a cytotoxic agent, an angiogenesis inhibitor, akinase inhibitor (including but not limited to a KDR and a TIE-2inhibitor), a co-stimulation molecule modulator or an immune checkpointinhibitor (including but not limited to anti-B7.1, anti-B7.2, anti-B7.3,anti-B7.4, anti-CD28, anti-B7RP1, CTLA4-Ig, anti-CTLA-4, anti-PD-1,anti-PD-L1, anti-PD-L2, anti-ICOS, anti-LAG-3, anti-Tim3, anti-VISTA,anti-HVEM, anti-BTLA, LIGHT fusion protein, anti-CD137, anti-CD137L,anti-OX40, anti-OX40L, anti-CD70, anti-CD27, anti-CD27L, anti-GAL9,anti-A2AR, anti-KIR, anti-IDO-1, anti-CD20), a dendriticcell/antigen-presenting cell modulator (including but not limited toanti-CD40 antibody, anti-CD40L, anti-DC-SIGN, anti-Dectin-1, anti-CD301,anti-CD303, anti-CD123, anti-CD207, anti-DNGR1, anti-CD205, anti-DCIR,anti-CD206, anti-ILT7), a modulator for Toll-like receptors (includingbut not limited to anti-TLR-1, anti-TLR-2, anti-TLR-3, anti-TLR-4,anti-TLR-4, anti-TLR-5, anti-TLR-6, anti-TLR-7, anti-TLR-8, anti-TLR-9),an adhesion molecule blocker (including but not limited to an anti-LFA-1antibody, an anti-E/L selectin antibody, a small molecule inhibitor), ananti-cytokine antibody or functional fragment thereof (including but notlimited to an anti-IL-18, an anti-TNF, or an anti-IL-6/cytokine receptorantibody), a bispecific redirected T cell or NK cell cytotoxicity(including but not limited to a BiTE®), a chimeric T cell receptor(CAR-T) based therapy, a T cell receptor (TCR)-based therapy, atherapeutic cancer vaccine, methotrexate, cyclosporin, rapamycin, FK506,a detectable label or reporter, a TNF antagonist, an anti-rheumatic, amuscle relaxant, a narcotic, a non-steroid anti-inflammatory drug(NSAID), an analgesic, an anesthetic, a sedative, a local anesthetic, aneuromuscular blocker, an antimicrobial, an antipsoriatic, acorticosteriod, an anabolic steroid, an erythropoietin, an immunization,an immunoglobulin, an immunosuppressive, a growth hormone, a hormonereplacement drug, a radiopharmaceutical, an antidepressant, anantipsychotic, a stimulant, an asthma medication, a beta agonist, aninhaled steroid, an epinephrine or analog, a cytokine, or a cytokineantagonist.

In an embodiment, a method of treating a cancer or in the prevention orinhibition of metastases from the tumors described herein, the CD137receptor agonist protein(s) can be used alone or in combination with oneor more additional agents, e.g., a chemotherapeutic, radiotherapy, orbiological agent. In some embodiments, the agent can include thefollowing: 13-cis-Retinoic Acid; 2-CdA; 2-Chlorodeoxyadenosine;5-Azacitidine; 5-Fluorouracil; 5-FU; 6-Mercaptopurine; 6-MP; 6-TG;6-Thioguanine; Abraxane; Accutane®; Actinomycin-D; Adriamycin®;Adrucil®; Afinitor®; Agrylin®; Ala-Cort®; Aldesleukin; Alemtuzumab;ALIMTA; Alitretinoin; Alkaban-AQ®; Alkeran®; All-transretinoic Acid;Alpha Interferon; Altretamine; Amethopterin; Amifostine;Aminoglutethimide; Anagrelide; Anandron®; Anastrozole;Arabinosylcytosine; Ara-C Aranesp®; Aredia®; Arimidex®; Aromasin®;Arranon®; Arsenic Trioxide; Arzerra™ Asparaginase; ATRA; Avastin®;Azacitidine; BCG; BCNU; Bendamustine; Bevacizumab; Bexarotene; BEXXAR®;Bicalutamide; BiCNU; Blenoxane®; Bleomycin; Bortezomib; Busulfan;Busulfex®; C225; Calcium Leucovorin; Campath®; Camptosar®;Camptothecin-11; Capecitabine Carac™; Carboplatin; Carmustine;Carmustine Wafer; Casodex®; CC-5013; CCI-779; CCNU; CDDP; CeeNU;Cerubidine®; Cetuximab; Chlorambucil; Cisplatin; Citrovorum Factor;Cladribine; Cortisone; Cosmegen®; CPT-11; Cyclophosphamide; Cytadren®;Cytarabine; Cytarabine Liposomal; Cytosar-U®; Cytoxan®; Dacarbazine;Dacogen; Dactinomycin; Darbepoetin Alfa; Dasatinib; Daunomycin;Daunorubicin; Daunorubicin Hydrochloride; Daunorubicin Liposomal;DaunoXome®; Decadron; Decitabine; Delta-Cortef®; Deltasone®; Denileukin;Diftitox; DepoCyt™; Dexamethasone; Dexamethasone Acetate; DexamethasoneSodium Phosphate; Dexasone; Dexrazoxane; DHAD; DIC; Diodex; Docetaxel;Doxil®; Doxorubicin; Doxorubicin Liposomal; Droxia™; DTIC; DTIC-Dome®;Duralone®; Duvelisib; Efudex®; Eligard™; Ellence™; Eloxatin™ Elspar®;Emcyt®; Epirubicin; Epoetin Alfa; Erbitux; Erlotinib; ErwiniaL-asparaginase; Estramustine; Ethyol Etopophos®; Etoposide; EtoposidePhosphate; Eulexin®; Everolimus; Evista®; Exemestane; Fareston®;Faslodex®; Femara®; Filgrastim; Floxuridine; Fludara®; Fludarabine;Fluoroplex®; Fluorouracil; Fluorouracil (cream); Fluoxymesterone;Flutamide; Folinic Acid; FUDR®; Fulvestrant; Gefitinib; Gemcitabine;Gemtuzumab ozogamicin; Gemzar; Gleevec™; Gliadel® Wafer; GM-CSF;Goserelin; Granulocyte-Colony Stimulating Factor (G-CSF); GranulocyteMacrophage Colony Stimulating Factor (G-MCSF); Halotestin®; Herceptin®;Hexadrol; Hexalen®; Hexamethylmelamine; HMM; Hycamtin®; Hydrea®;Hydrocort Acetate®; Hydrocortisone; Hydrocortisone Sodium Phosphate;Hydrocortisone Sodium Succinate; Hydrocortone Phosphate; Hydroxyurea;Ibrutinib; Ibritumomab; Ibritumomab Tiuxetan; Idamycin®; IdarubicinIfex®; Interferon-alpha; Interferon-alpha-2b (PEG Conjugate);Ifosfamide; Interleukin-11 (IL-11); Interleukin-2 (IL-2); Imatinibmesylate; Imidazole Carboxamide; Intron A®; ipilimumab, Iressa®;Irinotecan; Isotretinoin; Ixabepilone; Ixempra™; KADCYCLA®; Kidrolase(t) Lanacort®; Lapatinib; L-asparaginase; LCR; Lenalidomide; Letrozole;Leucovorin; Leukeran; Leukine™; Leuprolide; Leurocristine; Leustatin™Lirilumab; Liposomal Ara-C; Liquid Pred®; Lomustine; L-PAM;L-Sarcolysin; Lupron®; Lupron Depot®; Matulane®; Maxidex;Mechlorethamine; Mechlorethamine Hydrochloride; Medralone®; Medrol®;Megace®; Megestrol; Megestrol Acetate; MEK inhibitors; Melphalan;Mercaptopurine; Mesna; Mesnex™; Methotrexate; Methotrexate Sodium;Methylprednisolone; Meticorten®; Mitomycin; Mitomycin-C; MitoxantroneM-Prednisol®; MTC; MTX; Mustargen®; Mustine; Mutamycin®; Myleran®;Mylocel™; Mylotarg®; Navitoclax; Navelbine®; Nelarabine; Neosar®;Neulasta™; Neumega®; Neupogen®; Nexavar®; Nilandron®; Nilotinib;Nilutamide; Nipent®; Nitrogen Mustard Novaldex®; Nivolumab; Novantrone®;Nplate; Octreotide; Octreotide acetate; Ofatumumab; Oncospar®; Oncovin®;Ontak®; Onxal™; Oprelvekin; Orapred®; Orasone®; Oxaliplatin; Paclitaxel;Paclitaxel Protein-bound; Pamidronate; Panitumumab; Panretin®;Paraplatin®; Pazopanib; Pediapred®; PEG Interferon; Pegaspargase;Pegfilgrastim; PEG-INTRON™; PEG-L-asparaginase; PEMETREXED;Pembrolizumab; Pentostatin; Pertuzumab; Phenylalanine Mustard;Pidilizumab; Platinol®; Platinol-AQ®; Prednisolone; Prednisone;Prelone®; Procarbazine; PROCRIT®; Proleukin®; Prolifeprospan 20 withCarmustine Implant; Purinethol®; BRAF inhibitors; Raloxifene; Revlimid®;Rheumatrex®; Rituxan®; Rituximab; Roferon-A®; Romiplostim; Rubex®;Rubidomycin hydrochloride; Sandostatin®; Sandostatin LAR®; Sargramostim;Solu-Cortef®; Solu-Medrol®; Sorafenib; SPRYCEL™; STI-571; STIVAGRA™,Streptozocin; SU11248; Sunitinib; Sutent®; Tamoxifen Tarceva®;Targretin®; Tasigna®; Taxol®; Taxotere®; Temodar®; TemozolomideTemsirolimus; Teniposide; TESPA; Thalidomide; Thalomid®; TheraCys®;Thioguanine; Thioguanine Tabloid®; Thiophosphoamide; Thioplex®;Thiotepa; TICE®; Toposar®; Topotecan; Toremifene; Torisel®; Tositumomab;Trastuzumab; Treanda®; Tremelimumab; Tretinoin; Trexall™; Trisenox®;TSPA; TYKERB®; Urelumab; VCR; Vectibix™ Velban®; Velcade®; Venetoclax;VePesid®; Vesanoid®; Viadur™; Vidaza®; Vinblastine; Vinblastine Sulfate;Vincasar Pfs®; Vincristine; Vinorelbine; Vinorelbine tartrate; VLB;VM-26; Vorinostat; Votrient; VP-16; Vumon®; Xeloda®; Zanosar®; Zevalin™Zinecard®; Zoladex®; Zoledronic acid; Zolinza; or Zometa®, and/or anyother agent not specifically listed here that target similar pathways.

When two or more substances or principles are to be used as part of acombined treatment regimen, they can be administered via the same routeof administration or via different routes of administration, atessentially the same time or at different times (e.g. essentiallysimultaneously, consecutively, or according to an alternating regime).When the substances or principles are to be administered simultaneouslyvia the same route of administration, they may be administered asdifferent pharmaceutical formulations or compositions or part of acombined pharmaceutical formulation or composition, as will be clear tothe skilled person.

-   -   Also, when two or more active substances or principles are to be        used as part of a combined treatment regimen, each of the        substances or principles may be administered in the same amount        and according to the same regimen as used when the compound or        principle is used on its own, and such combined use may or may        not lead to a synergistic effect. However, when the combined use        of the two or more active substances or principles leads to a        synergistic effect, it may also be possible to reduce the amount        of one, more than one, or all of the substances or principles to        be administered, while still achieving the desired therapeutic        action. This may, e.g., be useful for avoiding, limiting or        reducing any unwanted side-effects that are associated with the        use of one or more of the substances or principles when they are        used in their usual amounts, while still obtaining the desired        pharmaceutical or therapeutic effect.

The effectiveness of the treatment regimen used according to theinvention may be determined and/or followed in any manner known per sefor the disease or disorder involved, as will be clear to the clinician.The clinician will also be able, where appropriate and on a case-by-casebasis, to change or modify a particular treatment regimen, so as toachieve the desired therapeutic effect, to avoid, limit or reduceunwanted side-effects, and/or to achieve an appropriate balance betweenachieving the desired therapeutic effect on the one hand and avoiding,limiting or reducing undesired side effects on the other hand.

Generally, the treatment regimen will be followed until the desiredtherapeutic effect is achieved and/or for as long as the desiredtherapeutic effect is to be maintained. Again, this can be determined bythe clinician.

In various embodiments, pharmaceutical compositions comprising one ormore CD137 receptor agonist proteins, either alone or in combinationwith prophylactic agents, therapeutic agents, and/or pharmaceuticallyacceptable carriers are provided herein. In various embodiments,nonlimiting examples of the uses of the pharmaceutical compositionsdisclosed herein include diagnosing, detecting, and/or monitoring adisorder, preventing, treating, managing, and/or ameliorating a disorderor one or more symptoms thereof, and/or in research. The formulation ofpharmaceutical compositions, either alone or in combination withprophylactic agents, therapeutic agents, and/or pharmaceuticallyacceptable carriers, are known to one skilled in the art (US PatentPublication No. 20090311253 A1).

As used herein, the phrase “effective amount” means an amount of CD137Lagonist protein that results in a detectable improvement (e.g., at leastabout 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%,70%, 75%, or more from baseline) in one or more parameters associatedwith a dysfunction of CD137L or with a CD137L-associated disease ordisorder.

Methods of administering a therapeutic agent provided herein include,but are not limited to, oral administration, parenteral administration(e.g., intradermal, intramuscular, intraperitoneal, intravenous andsubcutaneous), epidural administration, intratumoral administration,mucosal administration (e.g., intranasal and oral routes) and pulmonaryadministration (e.g., aerosolized compounds administered with an inhaleror nebulizer). The formulation of pharmaceutical compositions forspecific routes of administration, and the materials and techniquesnecessary for the various methods of administration are available andknown to one skilled in the art (US Patent Publication No. 20090311253A1).

In various embodiments, dosage regimens may be adjusted to provide foran optimum desired response (e.g., a therapeutic or prophylacticresponse). For example, a single bolus may be administered, severaldivided doses may be administered over time or the dose may beproportionally reduced or increased as indicated by the exigencies ofthe therapeutic situation. In some embodiments, parenteral compositionsare formulated in dosage unit form for ease of administration anduniformity of dosage. The term “dosage unit form” refers to physicallydiscrete units suited as unitary dosages for the mammalian subjects tobe treated; each unit containing a predetermined quantity of activecompound calculated to produce the desired therapeutic effect inassociation with the required pharmaceutical carrier.

An exemplary, non-limiting range for a therapeutically orprophylactically effective amount of a CD137 receptor agonist proteinprovided herein is about 0.1-100 mg/kg, (e.g., about 0.1-0.5, 0.1-1,0.1-10, 0.1-20, 0.1-50, 0.1-75, 1-10, 1-15, 1-7.5, 1.25-15, 1.25-7.5,2.5-7.5, 2.5-15, 5-15, 5-7.5, 1-20, 1-50, 7-75, 1-100, 5-10, 5-15, 5-20,5-25, 5-50, 5-75, 10-20, 10-50, 10-75, or 10-100 mg/kg, or anyconcentration in between). In some embodiments, the CD137 receptoragonist protein is present in a pharmaceutical composition at atherapeutically effective concentration, e.g., a concentration of about0.1-100 mg/ml (e.g., about 0.1-0.5, 0.1-1, 0.1-10, 0.1-20, 0.1-50,0.1-75, 1-10, 1-20, 1-50, 1-75, 1-100, 5-10, 5-15, 5-20, 5-25, 5-50,5-75, 10-20, 10-50, 10-75, or 10-100 mg/ml, or any concentration inbetween). Note that dosage values may vary with the type and/or severityof the condition to be alleviated. It is to be further understood thatfor any particular subject, specific dosage regimens may be adjustedover time according to the individual need and/or the professionaljudgment of the person administering or supervising the administrationof the compositions, and that dosage ranges set forth herein areexemplary only and are not intended to limit the scope or practice ofthe claimed composition.

EXAMPLES

1.1 Polypeptide Structure

-   A) Amino acids Met1-Gly20    -   Ig-Kappa-signal peptide, assumed signal peptidase cleavage site        after amino acid Gly 20.-   B) Amino acids Gln21-Val172    -   First soluble cytokine domain of the human CD137L ligand        (CD137L, amino acid 89-240 of SEQ ID NO: 1).-   C) Amino acids Gly173-Ser 180    -   First peptide linker element of SEQ ID NO: 2.-   D) Amino acids Gln181-Val332    -   Second soluble cytokine domain of the human CD137L ligand        (CD137L, amino acid 89-240 of SEQ ID NO: 1).-   E) Amino acids Gly333-Ser340.    -   Second peptide linker element of SEQ ID NO: 2.-   F) Amino acids Gln341-Val492    -   Third soluble cytokine domain of the human CD137L ligand        (CD137L, amino acid 89-240 of SEQ ID NO: 1).-   G) Amino acids Gly493-Cys513    -   Hinge-linker element of SEQ ID NO: 16.-   H) Amino acids Pro514-Lys731    -   Antibody Fc fragment domain of SEQ ID NO: 13.

The above CD137 receptor agonist protein is shown in SEQ ID NO: 25.

The indicated linkers may be replaced by other preferred linkers, e.g.as shown in SEQ ID NOs: 3-12.

The indicated Hinge-linker element may be replaced by other preferredHinge-linkers, e.g. as shown in SEQ ID NOs: 19-24.

It should be noted that the first and second peptide linkers do not needto be identical.

The signal peptide sequence (A) may be replaced by any other suitable,e.g. mammalian signal peptide sequence.

1.2 Gene Cassette Encoding the Polypeptide

The synthetic gene may be optimized in view of its codon usage for theexpression in suitable host cells, e.g. insect cells or mammalian cells.A preferred nucleic acid sequence is shown in SEQ ID NO: 37.

Example 2. Expression and Purification

2.1 Cloning, Expression and Purification of Fusion Polypeptides

The aforementioned fusion proteins are expressed recombinantly indifferent eukaryotic host cells employing the methods described below:

Method for Small Scale Expression of CD137 Receptor Agonist FusionProteins:

For small scale analysis of aforementioned CD137 receptor agonist fusionproteins, Hek293 cells are grown in DMEM+GlutaMAX (GibCo) supplementedwith 10% FBS, 100 units/ml Penicillin and 100 [mu]g/ml Streptomycin andare transiently transfected with a plasmid containing an expressioncassette for a fusion polypeptide and an appropriate selection marker,e.g. a functional expression cassette comprising a blasticidine,puromycin or hygromycin resistance gene. In those cases, where aplurality of polypeptide chains is necessary to achieve the finalproduct, the expression cassettes are either combined on one plasmid orpositioned on different plasm ids during the transfection. Cell culturesupernatant containing recombinant fusion polypeptide are harvestedthree days post transfection and clarified by centrifugation at 300×gfollowed by filtration through a 0.22 μm sterile filter.

Method for Large Scale Expression and Purification of CD137 ReceptorAgonist Fusion Proteins

For larger scale expression of CD137 receptor agonist fusion proteins,synthetic DNA cassettes encoding the aforementioned proteins areinserted into eukaryotic expression vectors comprising appropriateselection markers (e.g. a functional expression cassette comprising ablasticidin, puromycin or hygromycin resistance gene) and geneticelements suitable to enhance the number of transcriptionally activeinsertion sites within the host cells genome. The sequence verifiedexpression vectors is introduced by electroporation into suspensionadapted Chinese Hamster Ovary cells (CHO-S, Invitrogen). Appropriateselection pressure will be applied three days post-transfection totransfected cells. Surviving cells carrying the vector derivedresistance gene(s) are recovered by subsequent cultivation underselection pressure. Upon stable growth of the selected cell pools inchemically defined medium (PowerCHO2-CD, Lonza) at 37° C. and 7% CO2atmosphere in an orbital shaker incubator (100 rpm, 50 mm shakingthrow), the individual supernatants are analyzed by ELISA-assaysdetecting the aforementioned proteins and the cell pools with thehighest specific productivity are expanded in shake flasks prior toprotein production (orbital shaker, 100 rpm, shaking throw 50 mm).

For lab-scale protein production, individual cell pools are cultured for7-12 days in chemically defined medium (PowerCHO2-CD, Lonza) at 37° C.and 7% CO2 atmosphere in a Wave bioreactor 20/50 EHT (GE-Healthcare).The basal medium is PowerCHO2-CD supplemented with 4 mM Glutamax. Waveculture is started with a viable cell concentration of 0.3 to 0.4×10e6cells/ml and the following settings (for a five- or ten liter bag):shaking frequency 18 rpm, shaking ankle 7°, gas current 0.2-0.3 L/min,7% CO2, 36.5° C. During the Wave run, the cell culture is fed twice withPowerFeed A (Lonza), usually on day 2 (20% feed) and day 5 (30% feed).After the second feed, shaking frequency is increased to 22 rpm, as wellas the shaking ankle to 8°.

The bioreactor is usually harvested in between day 7 to day 12 when thecell viability drops below 80%. First, the culture supernatant isclarified using a manual depth filtration system (Millipore MillistakPod, MCOHC 0.054 m²). For Strep-tagged proteins, Avidin is added to afinal concentration of 0.5 mg/L. Finally, the culture supernatantcontaining the CD137 receptor agonist fusion protein is sterile filteredusing a bottle top filter (0.22 μm, PES, Corning) and stored at 2-8° C.until further processing.

For affinity purification Streptactin Sepharose is packed to a column(gel bed 2 ml), equilibrated with 15 ml buffer W (100 mM Tris-HCl, 150mM NaCl, pH 8.0) or PBS pH 7.4 and the cell culture supernatant isapplied to the column with a flow rate of approx. 4 ml/min.Subsequently, the column is washed with 15 ml buffer W and boundpolypeptide is eluted stepwise by addition of 7×1 ml buffer E (100 mMTris HCl, 150 mM NaCl, 2.5 mM Desthiobiotin, pH 8.0). Alternately, PBSpH 7.4 containing 2.5 mM Desthiobiotin can be used for this step.

Alternately to the Streptactin Sepharose based method, the affinitypurification is performed employing a column with immobilized Protein-Aas affinity ligand and an Akta chromatography system (GE-Healthcare). Asolid phase material with high affinity for the FC-domain of the fusionprotein is chosen: MABSelect Sure™ (GE Healthcare). Briefly, theclarified cell culture supernatant is loaded on a HiTrap MabSelectSurecolumn (CV=5 ml) equilibrated in wash-buffer-1 (20 mM Pi, 95 mM NaCl,pH7.2) not exceeding a load of 10 mg fusion protein per ml column-bed.The column is washed with ten column-volumes (10 CV) of aforementionedequilibration buffer followed by four column-volumes (4 CV) ofwash-buffer-2 (20 mM Pi, 95 mM NaCl, pH 8.0) to deplete host-cellprotein and host-cell DNA. The column is then eluted with elution buffer(20 mM Pi, 95 mM NaCl, pH 3.5) and the eluate is collected in up to tenfractions with each fraction having a volume equal to column-bed volume(5 ml). Each fraction is neutralized with an equal volume ofaforementioned wash-buffer-2. The linear velocity is set to 150 cm/h andkept constant during the aforementioned affinity chromatography method.The protein amount of the eluate fractions is quantitated and peakfractions are concentrated by ultrafiltration and further purified bysize exclusion chromatography (SEC).

SEC is performed on Superdex 200 10/300 GL or HiLoad 26/60 columns usingan Akta chromatography system (GE-Healthcare). The columns areequilibrated with phosphate buffered saline and the concentrated,affinity-purified polypeptide is loaded onto the SEC column with thesample volume not exceeding 2% (v/v) of the column-volume. In the caseof Superdex 200 10/300 GL columns (GE Healthcare), a flow rate of 0.5 mlper minute is applied. In the case of HiLoad 26/60 Superdex200 columns,a flow rate of 2.5 ml per minute is applied. The elution profile of thepolypeptide is monitored by absorbance at 280 nm.

For determination of the apparent molecular weight of purified fusionpolypeptide under native conditions a Superdex 200 column is loaded withstandard proteins of known molecular weight. Based on the elution volumeof the standard proteins a calibration curve is plotted and themolecular weight of purified fusion polypeptide is determined. TheFC-domain comprising CD137 receptor agonist fusion proteins elutes fromthe Superdex200 columns with an apparent molecular weight of approx.140-180 kDa, which would confirm the homodimerization of the matureCD137 receptor agonist fusion polypeptide by the Fc domain.

Example 3: Trivalent Control Protein

To compare the relative binding between hexavalent CD137 receptoragonist fusion proteins and the, homo-trimeric trivalent CD137 receptoragonist fusion proteins stabilized with bacteriophage RB69-FOLDON isexpressed in CHO-S cells and purified as described in the formersection. The sequence is shown in the table below:

SEQ ID NO Sequence 38 METDTLLVFVLLVWVPAGNGQGMFAQLVAQNVLLIDGP (TrivalentLSWYSDPGLAGVSLTGGLSYKEDTKELVVAKAGVYYVF controlFQLELRRVVAGEGSGSVSLALHLQPLRSAAGAAALALT protein)VDLPPASSEARNSAFGFQGRLLHLSAGQRLGVHLHTEARARHAWQLTQGATVLGLFRVGSGSSGSSGSSGSGYIEDAPSDGKFYVRKDGAWVELPTASGPSSSSSSAWSHPQFE K.

Example 4: Determination of the In Vitro Stability of CD137 ReceptorAgonist Proteins by Limited Protease Digestion

All CD137 receptor agonist proteins to be investigated will be expressedand purified as hexavalent Fc-Fusion protein as described in Example 1.The set will include CD137 receptor agonist proteins comprising theN297S mutation [according to the EU numbering system] in the CH2-domainand a hinge region that enables the formation of three disulfide bridgesand additionally lack the upper hinge lysine [K223, according to the EUnumbering system] which is mutated to glycine [K223G]. In a limitedprotease digestion assay, the aforementioned CD137 receptor agonistproteins comprising the N297S mutation and the K223G mutationsimultaneously in context of a three disulfide enabling hinge will becompared to CD137 receptor agonist proteins comprising the N297Smutation but have the K223 wildtype present either in the context of atwo disulfide or three disulfide enabling hinge region.

In addition CD137 receptor agonist proteins with the second linkerelement (iv) reduced to 4 amino-acids and the shortened hinge element(vi) will be investigated (e.g. SEQ ID NO: 32 and 34). Both engineeringstrategies (N297S combined with K223G mutation in context of a threedisulfide enabling hinge region) and shortage of linker elements (iv andvi) have a potential impact on the stability of the respectivemolecules.

The stability of different CD137 agonistic proteins of the presentinvention can be addressed by limited protease digestion in vitro. Forthis analysis, the aforementioned CD137 receptor agonist proteins areincubated with low concentrations of proteases (e.g. Trypsin, V8protease) at different temperatures (e.g. 4° C., 25° C., 37° C.) fordifferent amounts of time. Quantification of specific proteolyticfragments and their appearance over time can be subsequently measured bydifferent methods, like SDS-PAGE, analytical SEC or analyticalMass-Spectrometry methods known in the art (e.g. Nano-RP-HPLC-ESI-MSMS).As the investigated proteins have most of their sequences in common, thefaster appearance and enlarged quantities of specific proteolyticfragments from individual proteins over time can then be used to judgetheir relative stability and rank them to each other. With regard toprotease based decoy kinetics of the aforementioned CD137 receptoragonist proteins investigated, the following order regarding theirproteolytic stability is to be expected:

The CD137 receptor agonist proteins comprising the N297S and the K223Gand the three disulfide enabling hinge region simultaneously have aprolonged stability as compared to the CD137 receptor agonist proteinscomprising the N297S and wildtype K223 in the hinge region. The CD137receptor agonist proteins comprising the SEQ ID NO: 21 as hinge linkerhave a prolonged stability as compared to CD137 receptor agonistproteins comprising the SEQ ID NO: 16 as hinge linker element.

Example 5: Stability/Aggregation Test

The contents of monomers and aggregates are determined by analytical SECas described in Example 2. For this particular purpose the analysis isperformed in buffers containing physiological salt concentrations atphysiological pH (e.g. 0.9% NaCl, pH 7.4; PBS pH 7.4). A typicalaggregation analysis is done on a Superdex200 column (GE Healthcare).This column separates proteins in the range between 10 to 800 kDa.

For determination of the apparent molecular weight of purified fusionpolypeptide under native conditions a Superdex 200 column is loaded withstandard proteins of known molecular weight. Based on the elution volumeof the standard proteins a calibration curve is plotted and the apparentmolecular weight of purified fusion proteins of unknown molecular weightis calculated based on the elution volume.

SEC analysis of soluble, non-aggregated protein typically shows adistinct single protein peak at a defined elution volume (measured at ODat 280 nm or at OD 214 nm). This elution volume corresponds to theapparent native molecular weight of the particular protein. With regardto the definition of “monomer” in the case of FC-fusion proteins, theassembly of two polypeptide-chains is driven by the FC-part of theprotein and the functional unit is a protein consisting of two chains.This unit that contains two FC-linked polypeptide chains is defined as“monomer” in the case of Fc-fusion proteins regardless of being adimerized single-chain fusion polypeptide.

If protein aggregation occurs, the SEC analysis shows additional proteinpeaks with lower retention volumes. Protein oligomers potentially serveas aggregation seeds and a high content of oligomers potentially leadsto aggregation of the protein. Oligomers of large molecular weight andaggregates elute in the void volume of the Superdex200 column and cannotbe analyzed by SEC with respect to their native molecular weight.

Purified preparations of CD137 receptor agonist fusion proteins shouldpreferably contain only defined monomeric protein and only a very lowamount of oligomeric protein. The degree of aggregation/oligomerizationof a particular CD137 receptor agonist fusion protein preparation isdetermined on basis of the SEC analysis by calculating the peak areas ofthe OD280 diagram for the defined monomer and the oligomer/aggregatefraction, respectively. Based on the total peak area the percentage ofdefined monomer protein is calculated as follows:

monomer content [%]=[Peak area monomer protein]/[Total peak area]×100)

Example 6: Determination of the Equilibrium Binding Constants for Tri-and Hexavalent CD137 Receptor Ligand Constructs by QCM Analysis

The equilibrium binding constants (K_(D)) of trivalent and hexavalentconstructs of CD137 receptor ligand are calculated based on kineticbinding data (k_(on) and k_(off)) that are determined with an automatedbiosensor system (Attana A100). The A100 allows to investigate molecularinteractions in real-time based on the Quartz Crystal Microbalance (QCM)technique.

For this purpose the human CD137 receptor is immobilized to the surfaceof a carboxyl-activated QCM-chip. Subsequently the tri- or hexavalentCD137 receptor ligand, respectively, is used as an analyte at differentconcentrations (e.g. 0.5, 1, 2, 5, and 10 μg/ml) for analyzing thekinetic binding data for ligand-receptor binding (k_(on)) anddissociation (k_(off)). The analysis is done in real time and therespective K_(D) can be calculated:

K _(D) =k _(off) /k _(on).

The QCM analysis shows that the trivalent CD137 receptor ligand binds tothe respective immobilized CD137 receptor with a KD in the low nM-rangewith an expected K_(D) of 1-500 nM. However, hexavalent constructs ofCD137 receptor ligand show a higher binding affinity in the pM-rangetowards the respective immobilized CD137 receptor with an expected K_(D)of 1 pM-500 nM. A common characteristic of the kinetic binding data(k_(on) and k_(off)) is that the hexavalent constructs show fasterk_(on) in comparison to the trivalent constructs. In addition slowerdissociation (k_(off)) is commonly observed for the hexavalent ligandsif compared to the trivalent ligand.

Example 7: T Cell Proliferation Assay

To assess the T cell activation capability of the CD137 receptoragonist, T cells are purified from human buffy coat preparations bynegative selection using magnetic beads. Cells are labeled with CFSE andincubated with or without varying amounts of the CD137 receptor agonistand combined with an anti-human CD3 antibody for 2-5 days at 37° C. Dataon CFSE dilution as a means to measure cell division is acquired on aflow cytometer. IFNγ production is measured by an ELISA assay using cellculture supernatants and an anti-human IFNγ antibody for capture.

One expects to observe a clear augmentation of IFNγ secretion by bothCD4+ and CD8+ T cells when the CD137 receptor agonist is present in theT cell cultures along with the anti-human CD3 antibody. As well ashigher IFNγ production one expects to see more T cells to be driven intocell cycle by measuring CFSE dilution using flow cytometry. This woulddemonstrate a co-stimulatory effect of the CD137 receptor agonist in thecontext of T cell activation.

Example 8: CD137 Agonist Binding Assay

Primary, human T cells are isolated from fresh buffy coat preparationsusing negative selection and magnetic beads. Cells are seeded into24-well plates at 2×10e6 cells per well. T cells are incubated with ananti-human CD3 antibody (clone HIT3a, 1 μg/ml), anti-human CD28 antibody(clone CD28.2, 5 μg/ml) and varying amounts of Protein A (CD137L,10-1000 ng/ml) or simply left in medium as control. After 3 days at 37°C. cells are fluorescently labeled with anti-human CD137 and anti-humanCD4 or anti-human CD8 antibodies. CD137 fluorescence is assessed on aguava easyCyte flow cytometer within CD4+ and CD8+ T cell populations.

When comparing T cell populations incubated with anti-CD3 and anti-CD28antibodies to control cells left in medium alone, one expects to observea lower fluorescent signal for CD137 indicating an activation-induceddownregulation of the receptor. This effect can be stronger anddose-dependent, when cells are co-incubated with the CD137 agonist(Protein A), which indicates a supplementary effect caused by the CD137agonist (Protein A). Such results would suggest a binding of the CD137agonist (Protein A) to its receptor in vitro.

Example 9: Human In Vitro T Cell Proliferation Assay

Total T cells (human) purified by negative selection and magnetic beads(pan T cell isolation kit, Miltenyi Biotec) from the peripheral blood ofhealthy donors and stained with CFSE (CellTrace™ CFSE Cell ProliferationKit, for flow cytometry, ThermoFisher) and seeded into 24-well plates at2×10e6 cells per well. Cells were incubated at 37° C. for 5 days withmedia alone, soluble anti-CD3 antibody (clone OKT3 at 1 μg/ml) alone,anti-CD3 antibody plus anti-CD28 antibody (clone 28.2 at 1 μg/ml) oranti-CD3 antibody plus mature Protein A (SEQ ID NO: 27) at 10, 100 or1000 ng/ml, respectively.

On day 5, cells were washed and stained with DAPI (to exclude deadcells) and specific antibodies. Expression of Forward Scatter (FSC orsize) and proliferation dependent CFSE dilution was measured by flowcytometry with a Guava EasyCyte 12 Flow Cytometer (EMD Millipore). Dataanalysis was performed on a minimum of ten thousand recorded events persample with FlowJo 10.1 software (FlowJo, LLC). The percentage ofresponding cells was determined by gating on Forward Scatter and CFSEusing the media control to determine proper gate location. Cells thathad either increased cell size or decreased CFSE levels were labeled asresponding cells. The individual data from two biological replicatesfrom one donor is shown in below copied table (Quantification of T cellactivation) These results are consistent with results from additionaldonors and clearly showed that treatment of human T cells in vitro withProtein A enhances T cell activation and proliferation as compared toantibody stimulation alone.

Quantification of T Cell Activation.

Human T cell activation following treatment with Protein A in vitro % ofcells responding Stimulation Sample 1 Sample 2 Media  3  3 anti-CD3 5662 anti-CD3/28 87 85 anti-CD3 + APG1472  10 ng/ml 71 69 anti-CD3 +APG1472  100 ng/ml 75 71 anti-CD3 + APG1472 1000 ng/ml 66 75

Example 10: Receptor Binding Assay

For ELISA assays assessing functional binding of CD137 receptor agonistprotein of the invention to its corresponding receptor, coating ofmicrotiter plates was performed with 1 μg/ml CD137-Fc (Bio-Techne GmbH,Wiesbaden-Nordenstadt, Germany). After blocking with StartingBlock (LifeTechnologies GmbH, Darmstadt, Germany), wells were incubated withindicated concentrations of strep-tagged Protein A (SEQ ID NO: 28).Binding to its corresponding receptor was detected via its Strep Tag IIemploying the anti-StrepTag-peroxidase StrepTactin-HRP (1:5000, IBAGmbH, Goettingen, Germany) and subsequent detection of the convertedPeroxidase-substrate TMB one (Kem-En-Tec Diagnostics, Taastrup, Denmark)at a wavelength of 450 nm in an ELISA reader. FIG. 6 clearly depictsconcentration dependent binding of Protein A to its receptor.

1. (canceled)
 2. A CD137 receptor agonist protein comprising asingle-chain fusion polypeptide comprising: (i) a first soluble CD137Ldomain, (ii) a first peptide linker, (iii) a second soluble CD137Ldomain, (iv) a second peptide linker, and (v) a third soluble CD137Ldomain, and (vi) an antibody derived Fab- or Fc-fragment, wherein theCD137L domains (i), (iii) and (v) are N- and C-terminally shorteneddomains consisting of amino acids starting at an amino acid between 86and 90 and ending at amino acid 240, or 241, or 243 of SEQ ID NO:1. 3.The CD137 receptor agonist protein of claim 2, wherein the Fc fragmentof (vi) consists of the amino acid sequence as shown in SEQ ID NO: 13 or14 or amino acids 1-217 of SEQ ID NO: 13 or
 14. 4. The CD137 receptoragonist protein of claim 2, wherein the Fc fragment of (vi) is fused tothe C-terminal end of the third CD137L domain (v) via a hinge-linker ofany one of SEQ ID NOS: 16 or 19-24.
 5. The CD137 receptor agonistprotein of claim 2, wherein the Fab fragment of (vi) is fused to theN-terminal end of the first CD137L domain.
 6. The CD137 receptor agonistprotein of claim 5, wherein antibody Fab fragment of (vi) is fused tothe N-terminal end of the first CD137L domain via short G/C rich linkersaccording to SEQ ID NOS: 2-12.
 7. The CD137 receptor agonist protein ofclaim 2, wherein in at least one of the soluble CD137L domains, thestarting amino acid D86 or R88 or Q89 is replaced by a neutral aminoacid.
 8. The CD137 receptor agonist protein of claim 2, wherein thesoluble CD137L domains optionally comprises a mutation at position D86,L87, R88, Q89, D112, V118, A154, A174, A176, A188, T241, or at two ormore of said positions.
 9. The CD137 receptor agonist protein of claim2, wherein the first and second peptide linkers (ii) and (iv)independently have a length of 3-8 amino acids.
 10. The CD137 receptoragonist protein of claim 2, wherein the first and the second peptidelinkers (ii) and (iv) consist of the amino acid sequence according toSEQ ID NO:
 2. 11. The CD137 receptor agonist protein of claim 2, whichadditionally comprises an N-terminal signal peptide domain.
 12. TheCD137 receptor agonist protein of claim 2, wherein the polypeptide isfurther post-translationally modified.
 13. The CD137 receptor agonistprotein of claim 4, wherein the polypeptide is furtherpost-translationally modified.
 14. The CD137 receptor agonist protein ofclaim 13, wherein the post-translational modification comprisesmodification of the N-terminal glutamine to pyroglutamate.
 15. A nucleicacid molecule encoding the CD137 receptor agonist protein of claim 2, inan operative linkage with an expression control sequence.
 16. Anexpression vector comprising the nucleic acid molecule of claim
 15. 17.A cell or a non-human organism transformed or transfected with thenucleic acid molecule of claim
 15. 18. A pharmaceutical or diagnosticcomposition comprising as an active agent the CD137 receptor agonistprotein of claim 2 and one or more pharmaceutically acceptable carriers,diluents, excipients and/or adjuvants.